KML tracks from Google Tracks on Android do not convert correctly to GPX with gpsbabel. No trackpoints are output.
gpsbabel, as of version 1.4.4, does not support <gx:Track> in KML. This is a newish Google extension.
- http://old.nabble.com/Re%3A-Problem-with-KML-input-p32921193.html
- https://wiki.openstreetmap.org/wiki/List_of_GPS_trace_file_formats
- https://developers.google.com/kml/documentation/kmlreference#gxtrack
Save to GPX from Google Tracks. Even GPSPrune, contrary to what is stated on the OSM wiki page, above, does not seem to read the Google extension multitrack.